Question

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of substance will

• A. decrease twice
• B. increase two fold
• C. remain unchanged
• D. be a function of the molecular mass of substance

Answer 1

Answer: (B)

Remain unchanged.
This is because when you consider $1/6$ in place of $1/12$, since mass of carbon atom is sti $=2amu$ ( where amul is new amu unit and amu is old amu unit)
So now
$N_{A}1$
(avogadro's number) becomes half $(N/2$ ) since the weight of carbon corresponding to a becomes $6gm$ in place of 12. ( where $N_{A}1$ is new avogardo's number and $N_A$ is old avogardro's number)
And we know that mass of one mole of substance is $=N_A\times amu$
So new atomic mass $=N_{A}1\times amu1=N_{A}2\times 2amu=N_A\times amu=$
old atomic weight.